Washing machine and method of controlling spin drying thereof

ABSTRACT

A washing machine and a method of controlling spin drying thereof are provided. The method includes detecting an imbalance of a washing tub while rotating the washing tub after rinsing is completed, injecting water into the laundry in the washing tub based upon the imbalance of the washing tub, and detecting the imbalance of a washing tub while rotating the washing tub after the injecting of water. Therefore, since the imbalance detecting process of the washing tub can be reduced after rinsing is completed, the time necessary for beginning main spin drying of the laundry can be reduced.

This application claims the benefit of Korean Application No. 10-2006-0051599, filed on Jun. 8, 2006, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine and a method of controlling spin drying thereof, and more particularly, to a washing machine capable of reducing an imbalance detecting operation of a washing tub after rinsing is completed and a method of controlling spin drying thereof.

2. Discussion of the Related Art

Referring to FIG. 1, a washing machine includes a cabinet 10, a tub 21 installed in the cabinet 10 to receive wash water therein, and a washing tub 31 rotatably installed in the tub 21.

The cabinet 10 has a rectangular parallelepiped shape, and a door 15 for inserting and removing of the laundry is formed at a side of the cabinet 10. The tub 21 has a cylindrical shape with its one end opened and is supported by a spring 23 and a damper 25 in the cabinet 10. A drive motor 27 is installed at the rear of the tub to rotatably drive the washing tub 31. A drain path 28 is connected to a lower end of the tub 21 to drain water in the tub 21. A drain pump 29 is installed on the drain path 28.

The washing tub 31 has a cylindrical shape and rotates around a rotation shaft disposed almost horizontally. A plurality of through holes 33 are formed on a circumferential surface of the washing tub 31. A plurality of lifts 35 protruding inward are formed on an inner surface of the washing tub 31 so as to convey the laundry to an upper portion of the washing tub 31.

A method of controlling spin drying of the washing machine according to a related art will now be described with reference to FIG. 2.

When rinsing is completed (S10), a control unit (not shown) controls the drain pump 29 such that the drain path 28 is opened. Thus, wash water in the tub 21 is exhausted outside along the drain path 28 (S20).

The control unit detects an imbalance (UBi) of the washing tub 31 while rotating the drive motor 27 at a predetermined low speed, for example, from 80 rpm to 130 rpm (S30), and calculates the imbalance detecting number (ni) (S40). Next, the detected imbalance (UBi) is compared to a set value (UBset) for main spin drying (S50), when the detected imbalance of the washing tub 31 is the set value or less, the control unit controls the drive motor 27 of the washing tub 31 to increase the rotation speed, for example, to 800 rpm-1000 rpm, such that the main spin drying is performed (S60). On the other hand, when the detected imbalance (UBi) is more than the set value (UBset), the imbalance detecting operation is repeated. Here, when the imbalance detecting number (ni) is more than a maximum set number (nmax), an error is displayed on the external display (S80) and the drive motor 27 is stopped (S90).

However, the method of controlling the washing machine according to the related art has the following problems. Early in the process of detecting imbalance of the washing tub 31, because the laundry in the washing tub 31 contains sufficient water, there is a space for tumbling of the laundry in the washing tub 31. However, because of a centrifugal force, the amount of water contained in the laundry decreases with the lapse of time, thereby increasing the volume of the laundry, and consequently, reducing a space for tumbling of the laundry in the washing tub 31. This limits balancing of the laundry in the washing tub 31. Also, it takes more time to begin the main spin drying. In particular, the main spin drying may not begin, while repeating only the balancing and imbalance detecting operations, depending on the kind and the amount of the laundry.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a washing machine and method of controlling spin drying thereof that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

Therefore, an advantage of the present invention is to provide a washing machine capable of reducing the time required for an imbalance detecting operation of a washing tub after rinsing is completed and a method of controlling spin drying thereof.

Another advantage of the present invention is to provide a washing machine capable of reducing the whole spin drying time of the laundry and improving the cleaning capability for the laundry and a method of controlling spin drying thereof.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a method of controlling spin drying of a washing machine, the method including: detecting imbalance of a washing tub while rotating the washing tub after rinsing is completed; injecting water to the laundry in the washing tub depending on imbalance of the washing tub; and detecting imbalance of a washing tub while rotating the washing tub after the injecting of water.

In another aspect of the present invention, there is provided a method of controlling spin drying of a washing machine, the method including: detecting imbalance of a washing tub while rotating the washing tub after rinsing is completed; repeating the detecting of imbalance of the washing tub and calculating detecting number when the detected imbalance is more than a set value; injecting water into the washing tub when the detecting number is a set number or more; and detecting imbalance of the washing tub after the injecting of water.

In another aspect of the present invention, there is provided a washing machine including: a cabinet; a tub installed in the cabinet; a washing tub rotatably installed in the tub; a drive motor that rotates the washing tub; a circulation pump that draws water in the tub and circulates the water; a drain pump that drains water in the tub; an imbalance detection unit that detects imbalance of the washing tub; and a control unit. The control unit controls the drive motor and the imbalance detection unit to detect imbalance of the washing tub while rotating the washing tub after rinsing is completed, and when the detected imbalance is more than a set value, the control unit controls the circulation pump to inject water into the washing tub and controls the imbalance detection unit to detect imbalance of the washing tub.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

In the drawings:

FIG. 1 is a cross-sectional view of a related art washing machine;

FIG. 2 is a flowchart illustrating a method of controlling spin drying of the washing machine of FIG. 1;

FIG. 3 is a cross-sectional view of a washing machine according to a first embodiment of the present invention;

FIG. 4 is a block diagram of the washing machine of FIG. 3;

FIG. 5 is a block diagram of a washing machine according to a second embodiment of the present invention;

FIG. 6 is a flowchart illustrating a method of controlling spin drying of a washing machine according to a third embodiment of the present invention;

FIG. 7 is a flowchart for illustrating a method of controlling spin drying of a washing machine according to a fourth embodiment of the present invention; and

FIG. 8 is a flowchart illustrating a method of controlling spin drying of a washing machine according to a fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

Referring to FIG. 3, a washing machine includes a cabinet 110, a tub 121 supported by a spring 123 and a damper 125 in the cabinet 110 to receive wash water therein, and a washing tub 151 rotatably installed in the tub 121.

The cabinet 110 has an approximately parallelepiped shape, and a door 115 for inserting and removing of the laundry is disposed on a front side of the cabinet 110.

The tub 121 has a cylindrical shape with its one side opened and is supported by the spring 123 and the damper 125. A washing tub 151 having a cylindrical shape is rotatably installed in the tub 121. A plurality of through holes 153 are formed on a circumferential surface of the washing tub 151. A plurality of lifts 155 protruding inward are formed in the washing tub 151 so as to convey the laundry to an upper portion during rotation of the washing tub 151. A drive motor 127 is disposed at the rear end of the tub 121 to rotate the washing tub 151.

A drain path 131 is formed at a side under the tub 121 to drain wash water in the tub 121, and a drain pump 133 is disposed on the drain path 131. A circulation passage 135 is formed at another side under the tub 121 so as to draw wash water received in the tub 121 and inject the wash water from an upper portion of the tub 121 to the inside of the washing tub 151. A circulation pump 137 is disposed on the circulation passage 135. A water supply unit 141 is disposed above the tub 121 to supply water into the tub 121. The water supply unit 141 includes a water supply pipe 143 connected to a water pipe, and a water supply valve 145 for opening and closing the water supply pipe 143. A detergent supply unit 147 is installed to the water supply pipe 143 so as to supply detergent into the tub 121.

Referring to FIG. 4, the washing machine according to the present invention includes an imbalance detection unit 163 for detecting an imbalance of the washing tub 151, and a control unit 161. The control unit 161 controls the drive motor 127, the water supply valve 145, the drain pump 133, and the circulation pump 137 based on a detection result of the imbalance detection unit 163.

According to the above-mentioned structure, when rinsing is completed, the control unit 161 controls the imbalance detection unit 163 to detect an imbalance of the washing tub 151 while rotating the washing tub 151 at low speed (e.g., from 80 rpm to 130 rpm) by controlling the drive motor 127. When the detected imbalance is a set value or less, the control unit 161 rotates the washing tub 151 at high speed (e.g., from 800 rpm to 1300 rpm) to perform main spin drying by controlling the drive motor 127. When the detected imbalance is more than the set value, the control unit 161 controls the circulation pump 137 to inject water into the washing tub 151 and controls the imbalance detection unit 163 to detect the imbalance of the washing tub 151. Here, the control unit 161 may control the water supply valve 145 to additionally supply water into the tub 121 before injecting water into the washing tub 151. Alternatively, the control unit 161 may control the drain pump 133 to stop exhausting water such that a determined amount of water remains in the tub 121 before injecting water into the washing tub 151.

Hereinafter, a washing machine according to a second embodiment of the present invention will now be described with reference to FIG. 5. Like reference numerals refer to like elements in FIGS. 4 and 5, and specific description thereof will be omitted. Referring to FIG. 5, the washing machine includes an imbalance detection unit 163 for detecting an imbalance of the washing tub 151, a detecting number calculation unit 165 for calculating the imbalance detecting number, and a control unit 161. The control unit 161 controls the drive motor 127, the water supply valve 145, the drain pump 133, and the circulation pump 137 based on the detection result of the imbalance detection unit 163 and the calculated result of the detecting number calculation unit 165.

According to the above-mentioned structure, when rinsing is completed, the control unit 161 controls the imbalance detection unit 163 to detect an imbalance of the washing tub 151 while rotating the washing tub 151 at low speed (from 80 rpm to 130 rpm) by controlling the drive motor 127. When the detected imbalance is a set value or less, the control unit 161 rotates the washing tub 151 at high speed (from 800 rpm to 1300 rpm) to perform main spin drying by controlling the drive motor 127. Meanwhile, when the detected imbalance is more than the set value, the control unit 161 allows the detecting number calculation unit 165 to calculate the imbalance detecting number while repeating the imbalance detection. When the imbalance detecting number is more than a set number, the control unit 161 controls the circulation pump 137 to inject water into the washing tub 151 and controls the imbalance detection unit 163 to detect an imbalance of the washing tub 151. Here, the control unit 161 may control the water supply valve 145 to additionally supply water into the tub 121 before injecting water into the washing tub 151. Alternatively, the control unit 161 may control the drain pump 133 to stop exhausting water such that a determined amount of water remains in the tub 121 before injecting water into the washing tub 151.

Hereinafter, methods of controlling the washing machine having the above-described structure will now be described with reference to FIGS. 6 and 7.

Referring to FIG. 6, when rinsing is completed (S110), the control unit 161 drives the drain pump 133 to drain water in the washing tub 151 (S120). Next, the control unit 161 controls the drive motor 127 such that the washing tub 151 rotates at low speed (for example, from 80 rpm to 130 rpm) (S130), and controls the imbalance detection unit 163 to detect an imbalance (UBi) of the washing tub 151 (S140). Also, the control unit 161 controls the detecting number calculation unit 165 to calculate the imbalance detecting number (ni) (S150).

The imbalance detected by the imbalance detection unit 163 is compared to a set value (UBset) (S160). When the detected imbalance is the set value or less, the control unit 161 increases the rotation speed of the washing tub 151 by controlling the drive motor 127 to perform main spin drying (S170).

Meanwhile, when the detected imbalance is more than the set value (S160), the control unit 161 compares the calculated imbalance detecting number to a maximum set number (nmax) (S180). Here, the maximum set number defines the upper limit of the detection number, where the balancing process can be carried out so as to prevent the imbalance detection from being indefinitely repeated. When the detecting number is the maximum set number or more, the control unit 161 displays an error message such as a warning on a display unit (not shown) (S181), and stops the drive motor 127 (S182).

When the calculated imbalance detecting number is less than the maximum set number (S180), the control unit 161 stops the drive motor 127 (S190) and controls the water supply valve 145 to additionally supply a determined amount of water into the tub 121 (S200). Next, the control unit 161 drives the circulation pump 137 so as to inject a predetermined amount of water into the laundry in the washing tub 151 (S210). As illustrated in FIG. 7, after stopping the drive motor 127 (S190), when the imbalance detecting number (ni) is the set number (nset) or more (S195), the control unit 161 may stop driving the drain pump 133 (S205) and circulate unexhausted water so as to inject the water to the laundry.

The control unit 161 calculates driving time (T2i) of the circulation pump 137 (S220) and then compares the calculated driving time to a set time (S230). When the calculated driving time is the set time or more, the control unit 161 considers that the predetermined amount of water has been injected to the laundry and stops the circulation pump 137 (S240). Then, the control unit 151 repeatedly performs the above-described process of controlling the drive motor 127 so as to rotate at low speed (S130) and controlling the imbalance detection unit 163 to detect an imbalance of the washing tub 151 (S140).

Hereinafter, a method of controlling a washing machine according to another embodiment of the present invention will now be described with reference to FIG. 8. Like reference numerals refer to like elements in FIGS. 6 to 8, and specific description thereof will be omitted.

Referring to FIG. 8, when rinsing is completed (S110), the control unit 161 drives the drain pump 133 to drain water in the washing tub 151 (S120). Next, the control unit 161 controls the drive motor 127 such that the washing tub 151 rotates at low speed (S130) and controls the imbalance detection unit 163 to detect an imbalance (UBi) of the washing tub 151 (S140). Also, the control unit 161 controls the detecting number calculation unit 165 to calculate an imbalance detecting number (ni) (S150).

The detected imbalance is compared to the set value (UBset) (S160). When the detected imbalance is more than the set value, the control unit 161 compares the imbalance detecting number (ni) calculated by the detecting number calculation unit 165 to the maximum set number (nmax) (S180). When the imbalance detecting number is less than the maximum set number, the control unit 161 stops the drive motor 127 (S190). Also, when the detected imbalance detecting number (ni) is less than the set number (nset) (S300), the control unit 161 repeats the process of driving the drive motor 127 at low speed (S130) and controlling the imbalance detection unit 163 to detect imbalance of the washing tub 151.

Meanwhile, when the imbalance detecting number is the set number or more (S300), the control unit 161 injects a predetermined amount of water into the washing tub 151 (S310). Here, water may be injected into the washing tub 151 by additionally supplying water (S200) and then driving the circulation pump 137, as described with reference to FIG. 6. Alternatively, the control unit 161 may stop exhausting water by stopping the drain pump 133 and then inject water while circulating unexhausted water by driving the circulation pump 137, as described with reference to FIG. 7.

When a predetermined amount of water is injected into the washing tub 151, the control unit 161 repeats the process of controlling the drive motor 127 to rotate the washing tub 151 and detecting the imbalance of the washing tub 151 until the main spin drying is performed.

A washing machine and a method of controlling spin drying thereof have the following effects.

According to the present invention, an increase in the volume of laundry due to decrease in moisture can be reduced by supplying moisture to the laundry in which moisture is exhausted due to rotation of a washing tub. Therefore, space for tumbling of the laundry may be obtained to reduce the time required for the imbalance detecting operation of the washing tub.

Also, an imbalance detecting number of the washing tub is calculated, the draining of the tub is stopped based on the calculation result, and then unexhausted water is circulated to inject the water into the laundry in the washing tub. Therefore, an operation of unnecessarily injecting water into the laundry may be reduced to prevent the waste of water and time. As a result, the time necessary for the whole spin drying process may be reduced.

In addition, a predetermined amount of water is supplied into the tub before injecting water into the laundry in the washing tub, and the supplied water is circulated and injected into the laundry, and thus the imbalance detection of the washing tub can have a rinsing effect. Therefore, a rinsing operation can be reduced while maintaining the same rinsing effect to reduce the whole washing time. Also, when the rinsing operation is not reduced, the cleaning capability for the laundry may be improved.

It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A method of controlling spin drying of a washing machine, the method comprising: detecting an imbalance of a washing tub while rotating the washing tub after rinsing is completed; injecting water into the laundry in the washing tub based upon the imbalance of the washing tub; and detecting the imbalance of the washing tub while rotating the washing tub after the injecting of water.
 2. The method of claim 1, further comprising supplying water into a tub before the detecting of imbalance of the washing tub after the injecting of water.
 3. The method of claim 1, further comprising stopping a draining of water in a tub before the injecting of the water, wherein unexhausted water is circulated and supplied to the laundry during the injecting of water.
 4. The method of claim 1, further comprising, when the detected imbalance is a set value or less, performing a main spin drying by increasing a rotation speed of the washing tub.
 5. The method of claim 4, further comprising supplying water into a tub before the detecting of an imbalance of the washing tub after the injecting of water.
 6. The method of claim 4, further comprising stopping a draining of water in a tub before the injecting of the water, wherein unexhausted water is circulated and supplied to the laundry during the injecting of water
 7. The method of claim 6, further comprising calculating an imbalance detecting number after the detecting of an imbalance of washing tub, wherein draining of water in the washing tub is stopped when the imbalance detecting number is a set number or more.
 8. A method of controlling spin drying of a washing machine, the method comprising: detecting an imbalance of a washing tub while rotating the washing tub after rinsing is completed; repeating the detecting of an imbalance of the washing tub and calculating a detecting number when the detected imbalance is more than a set value; injecting water into the washing tub when the detecting number is a set number or more; and detecting an imbalance of the washing tub after the injecting of water.
 9. The method of claim 8, further comprising, when the detected imbalance is the set value or less, performing a main spin drying by increasing a rotation speed of the washing tub.
 10. The method of claim 8, further comprising supplying water into a tub before the injecting of water, wherein water in the tub is drawn out and then is injected into the tub during the injecting of water.
 11. The method of claim 8, further comprising stopping a draining of water in a tub before the injecting of water, wherein water remaining in the tub is circulated and injected during the injecting of water.
 12. A washing machine comprising: a cabinet; a tub installed in the cabinet; a washing tub rotatably installed in the tub; a drive motor that rotates the washing tub; a circulation pump that draws water in the tub and circulates the water; a drain pump that drains water in the tub; an imbalance detection unit that detects an imbalance of the washing tub; and a control unit, wherein the control unit controls the drive motor and the imbalance detection unit to detect an imbalance of the washing tub while rotating the washing tub after rinsing is completed, and when the detected imbalance is more than a set value, the control unit controls the circulation pump to inject water into the washing tub and controls the imbalance detection unit to detect an imbalance of the washing tub.
 13. The washing machine of claim 12, wherein, when the detected imbalance is the set value or less, the control unit controls the drive motor to increase a rotation speed of the washing tub to a predetermined speed.
 14. The washing machine of claim 12, further comprising: a water supply path; and a water supply valve that opens and closes the water supply path, wherein the control unit controls the water supply valve to supply water into the tub before injecting water into the washing tub.
 15. The washing machine of claim 12, wherein the control unit controls the drain pump to stop draining of water in the tub before injecting water into the washing tub.
 16. The washing machine of claim 12, further comprising a detecting number calculation unit that calculates an imbalance detecting number of the imbalance detection unit, wherein the control unit controls the circulation pump to inject water into the washing tub, when the detected imbalance is more than the set value and the imbalance detecting number is a set number or more.
 17. The method of claim 8, further comprising, stopping the drive motor when the detecting number is less than a maximum set number before the injecting of water into the washing tub.
 18. The method of claim 17, further comprising driving the drive motor when the detecting number is less than a set number before the injecting of water into the washing tub. 